Transducer unit for printing type element



Dec. 3, 1963 D. R. WILLIAMS 3,112,693

TRANSDUCER UNIT FOR PRINTING TYPE ELEMENT 3 Shasta-Sheet 1 Filed March 6. 1961 [1114 I'll r1111 4:,

' INVENTOR. DAVID R.WILLIAMS ATTOAIVE) 3 Sheets-Shet 2 xxxx,

D. R. WILLIAMS TRANSDUCER UNIT FOR PRINTING TYPE ELEMENT Filed March 6. 1961 Dec. 3, 1963 7 \xxw a 114% 6 110K xx Dec. 3, 1963 D. R. WILLIAMS 3,112,693-

TRANSDUCER UNIT FOR PRINTING TYPE ELEMENT I Filed March 6, 1961 S'Sheets-Sheet 3 i/ H/ 11 9 H/ 4 5 j a D 120 j E f 302265 P0715357! j 2 f, 0/ I J H/ K :5 M /V 5 o P r? a K j s 0/ 7 (f j v W 5 z X 5 z IN VEN TOR. DAVID R.WILLIM5 as i United States Patent 3,112,6h3 TRANSDUCER UNIT FUR PRINTING TYPE ELEMENT David R. Williams, Cardiili, Calif., assignor, by mesne assignments, to Daystrom Incorporated, Murray Hill,

N-I, a corporation of Texas Filed Mar. 6, 1%1,Ser. No. 93,461 11 Claims. (Cl. 101-102) This invention relates to printing apparatus and more particularly to a printer having a relatively small number of moving parts.

Existing printers, particularly those of the line-by-line type employed to provide the print-out from a digital computer, require many mechanical parts. In one type of l-ine-by-line printer, for example, each column of characters requires a separate printing disc, or wheel, each having all of the necessary characters positioned, or raised, upon the periphery thereof. Also, a relatively complex drive mechanism is required to rotate each printing disc to place the desired character in a printing position. While these printers perform quite well, due to the large number of mechanical parts, they are subject to mechanical failure and also are somewhat costly.

Even electrically actuated typewriters capable of typing out coded input signals require a separate mechanically actuated type element for each character to be printed. These separate type elements, typically more than forty in number, are subject to mechanical wear and tear.

It is, therefore, an object of this invention to obviate many of the disadvantages of the prior art printers.

Another object of this invention is to reduce the number of mechanical parts required for printing apparatus.

Another object of this invention is to improve the reliability of printers.

, In accordance with a preferred embodiment of this invention, a solid state printer is formed with a relatively small number of mechanical parts. In a typical case, the printer would include a printing surf-ace, or paper roller, an ink ribbon positioned immediately above the printing surface and the novel type assembly or unit of this invention positioned above the inked ribbon such that, when actuated by a transducer unit, characters are impressed on the printing surface through the inked ribbon. The novel type unit itself includes a plurality of individual type elements arranged in a predetermined configuration such that, by actuating selected ones of the individual type elements, the desired characters are formed and impressed upon the printing surface.

Each of the individual type elements of the type assembly is actuated 'by a corresponding elongated member, each member comprising a slab or bar of an electrostr-ictive material such as a ferroelectric ceramic one end of which is fixedly secured in said transducer (away from the printing surface). Conductive plates are placed on either side of each of the slabs of ferroelectric material and are connected to a decoding matrix which selectively applies a voltage to various of the plates thereby to establish an electric field across selected ones of the slabs of ferroelectric material. Those slabs subjected to the electric field distort or expand such as to actuate their associated type element to form the desired characters on the printing surface.

In another embodiment of the invention, printing may be aided by a hammer, striking bar, or roller which may impress the printing surface against the actuated type elements.

Further advantages and features of this invention will become apparent upon consideration of the following description read in conjunction with the drawings wherein:

FIGURE 1 is a part schematic and part perspective view of an individual electrostrictive type element;

A aliases Patented Dec. 3., 1963 FIGURE 2 is a side view partially cut-away of a type assembly comprising several individual type elements of the kind illustrated in FIG. 1, which is capable of forming different characters;

FIGURE 3 is an end view of the type assembly of FIG. 2, taken through the section 3-3;

FIGURE 4 is an enlarged pictorial view of a printer using the type assembly illustrated in FIGS. 2 and 3 and includes a block diagram of the electrical circuitry necessary to actuate the printer;

FIGURE 5 illustrates typical character configurations that may be formed by the type assembly of FIGS. 2 and 3 to represent the numerals 0 through 9, inclusive;

FIGURE 6 is an end view of another type assembly similar to that of FIGS. 2 and 3, but adapted to form alphanumeric characters;

FIGURE 7 illustrates in outline form the alphanumeric character configurations that may be formed utilizing the type configurations of FIG. 6; and

FIGURE 8 is a schematic diagram of a decoding matrix that may be used in the printer illustrated in FIG. 4 to drive the type assembly illustrated in FIG. 6 to form the characters of FIG. 7.

The invention is perhaps most easily explained in its embodiment in a printer typically of the line-by-line type that is capable of printing the output of a digital computer. The invention, however, may be used in any printer which causes characters or symbols to be imprinted by means of a mechanical motion on a printing surface such as paper or other suitable material. Typically, an inked ribbon is interposed between the type characters and the printing surface. A motion imparted either by the type character or by the printing surface causes the type characters and the printing surface to be brought together sharply so as to cause an impression of the character on the printing surface.

All crystals, in fact all solid insulators, have a second order elect-restrictive effect in which a distortion occurs in the crystal that is proportional to the square of the electric displacement in the crystal. This distortion is quite small except in ferroelectric materials, such as Rochelle salt, barium titanate, lead zirconate titanate, etc., and is apparently due to the stresses induced by changing the alignment of the ferroelectric domains upon electrification. This electrostrictive effect in ceramic barium titanate typically may produce distortions of seven parts in ten thousand for an electric field strength of 30,000 volts per centimeter. This distortion occurs in the direction of the electric field. However, due to Poissons coupling, distortions of approximately one-third of this amount occur in the other two orthogonal directions with respect to the direction of the electric field.

This electrostrictive effect may perhaps be better understood by reference to FIG. 1. In FIG. 1 there is illustrated a wafer or slab 10 of an electrostrictive material such as barium titanate. Lower and upper conductive plates or electrodes 12 and 14 are placed or deposited on either side of the slab If such as to form a single condenser element wherein the slab It) forms the dielectric of the condenser. Each of plates 12 and 14 on the slab 10 is fixedly secured at one end to a support member 16 which may be a non-conductor that is fairly rigid so as to provide adequate support for the printing element 18 which includes the slab 10, the lower and upper plates 12 and 14, and a type element 20. The type element 20, which may be similar to the type face end of a conventional typewriter key, is mounted at the other end of the printing element 18, i.e., that end away from the support member 16. The characters to be printed or elements thereof may appear in a raised position on the face of the character or type element 2 5. However, as will be described more fully hereinafter,

in accordance with the invention, the type element 20 des rably is an element of or a portion of a full character and may be combined with other similar type or character elements attached to other electrostrictive slabs to form full characters.

A source of potential, illustrated as a battery 24, has one terminal connected through a switch 26 to the upper plate 14 of the printing element 18 and the other terminal connected to the lower plate 12. Although the source of potential is illustrated as a DC. source, it may also be a source of alternating potential as will become apparent hereinafter.

In any event, with the closing of the switch 26, a DC. potential from the battery 24 is applied across the slab It) so as to establish an electric field, illustrated by the arrows 28. This electric field 28 causes a distortion or expansion of the slab 10 in a direction parallel to the electric field and also in the two orthogonal directions 30 and 32 with respect to the direction of the electric field 28. By fixedly mounting the printing element 18 to the support member 16, the expansion or distortion in the direction 32, for example, is manifested by an extension in the length of the slab 10. This motion or growth of slab 10 produces a corresponding motion of the type element 20 as illustrated by the dotted lines 34. This motion of the type 20 is sufficient to cause the type 20 to form a character element (not shown) on a printing surface (not shown in this view).

Aside from the geometrical considerations, mainly there are three variables which should be considered in constructing a solid state printing element 18. These variables are physical displacement, force of displacement, and the intensity of the electric field causing the displacement. The physical displacement and force are both directly proportional to the electric field causing them, but are inversely proportional to each other. Therefore, for a particular geometric configuration of the slab 10 it is necessary to make a compromise between the displacement and force if a reasonable electric field strength is to be employed.

For example, a thin bar of electrostrictive material, 7.7 inches by 0.1 inch by 0.050 inch of 95% barium titanate and calcium titanate, has been found to produce an expansion of approximately 0.010 inch in the driving direction 32 in practical cases. The use of thinner bars, of course, facilitates the use of low voltages to accommodate transistor drive circuitry.

The plates 12 and 14 may serve to strengthen the slab material which typically is quite brittle. The plates 12 and 14 may be formed by vacuum deposition techniques or may be painted on the slab 10 and then baked. Other known techniques, of course, may be used to form the printing element 18.

Using an actuating means of this type described in conjunction with FIG. 1, a printer illustrated in FIG. 4 may be constructed. The printer comprises a printing head, generally designated as 36 and including a transducer unit 36' and a type unit 37, as illustrated in FIGS. 2 and 3 for forming different characters on a printing surface 66 (FIG. 4) as will be described. Thus, in FIG. 2 there appears a partially cut-away and enlarged side view of a printing head 36 having seven printing element 18A, 18B, 18C, 18D, 18E, 18F and 18G arranged generally parallel to each other and in a predetermined configuration. The particular configuration of the printing elements is more easily observed by reference to FIG. 3 which is a section view of the printing assembly 36 taken through the section 33 of FIG. 2. Each of these individual printing elements 18 comprises, as de scribed in FIG. 1, an electrostrictive slab 10 sandwiched between plates or electrodes 12 and 14 (FIG. 1) adapted to establish an electric field 28 (FIG. 1) through each slab 10. Each printing element 18 has suitably attached to one end an individual piece of type 20 which in operation is selectively driven by its respective slab 10 to effect printing.

As viewed in FIG. 4, two of the pieces of type 20 are illustrated as protruding from the lower portion of the type assembly 36. To facilitate the construction of the type assembly 36, the printing elements 18 (FIGS. 2 and 3) are enclosed by an outer case 38 which may serve as the lower plate 12 (FIG. 1) of the printing elements 18. The case 38 may be formed of sheet metal, properly stamped and welded or soldered to provide the two rectangular enclosures 42 and 44 which enclose the several printing elements 18.

Typically, the printing elements 18A through 18G, inclusive, are placed lengthwise of the case 38 in the two rectangular areas 42 and 44 in a configuration (as illustrated in FIG. 3) such as to be capable of selectively forming the numerals illustrated in FIG. 5. The electrostrictive slabs 10 which form the printing elements 18B, E, and F are placed in the lower rectangular area 42 such that the case 38 forms one of the electrodes necessary to establish the electric field 28 (FIG. 1) in the slabs 10. The remaining electrostrictive slabs 10 which form the remaining printing elements 18A, C, D, and G are placed in the upper rectangular portion 44 such that the case 38 forms one of the electrodes necessary to establish the electric field 28 (FIG. 1) in the slabs 10. The case 38 is grounded. The remaining electrodes 46 from each of the printing elements 18 are placed against the respective slabs 10 and connected by leads 48 which are passed through the non-conductive support member 16 on the upper end of the type assembly 36 to a switch 50 (FIG. 4).

Care must be taken to insure that the remaining electrodes 46 are electrically insulated from each other to permit the individual printing elements 18A through 186 to be selectively actuated. The upper and lower enclosures 42 and 44 may each be filled with a suitable potting compound to hold the several printing elements 18 in position.

To continue the description of the printer of FIG. 4, a source of potential 24 is connected to the switch 50 as are the outputs of a decoding matrix 52. In turn, the decoding matrix is connected to receive an input from a keyboard or other suitable source such as the output of a computer illustrated by the block 54. The keyboard 54 may provide either an electrical or mechanical signal to the decoding matrix 52 to actuate one or more of the several output lines 56 from the decoding matrix 52 which in turn connects the source of potential 24 to one or more of the conductors 48 leading to the several printing elements 18A through 18G, inclusive.

The switch 50 may constitute no more than several electrical relays or other switching devices which are gated to pass the voltage signal from the source 2-4 upon the application of an input signal from the decoding matrix 52. The decoding matrix 52 may be of a conventional type adapted to decode, for example, a keyboard signal representing a certain numeral or character to actuate the required ones of the printing elements 18A through 18G, inclusive, to form the desired characters (FIG. 5). A suitable matrix that can be employed with this invention is described in an article beginning on page of the June 1960 issue of Control Engineering, entitled Eliminating Diode Redundancy in Encoding and Decoding Matrices, by Arthur Freilich. To facilitate this description, the letter portion of the reference numerals 18 correspond to the letters used in the matrix illustrated in FIG. 9 of this article. If the matrix of the article is used its input rotary switch is actuated by the keyboard 54 and its output lamps are. replaced by the winding of the relays in the switch 50.

If an input directly from a computer is used, it may be necessary to use an additional matrix (not shown) to converte from its particular code tosignal the printing of the desired character.

The keyboard 54 may be also coupled to an electromechanical actuator 58 which acts through a mechanical linkage 64) to drive, or force, a striking bar, or roller 62 against the type elements 28 of'the type assembly 36 to aid in printing. An inked ribbon 64 and a printing surface 66, such as a suitable paper material, may be disposed between the type elements 20 and the roller 62. The paper may ride upon an additional support member 68 and be driven in the direction indicated by the arrow '72 by a suitable means (not shown).

In its operation, if in the keyboard 54 numeral 3 key, for example, is depressed thereby to print the character 3, in the general configuration illustrated in FIG. 5, the decoding matrix 52 receives a voltage signal, for example, on its numeral 3 input. In turn, the decoding matrix 52 generates output signals on those five of its output lines 56 necessary to form the numeral 3 (FIG. 5). The switch 58 applies the potential from the source 24 on a corresponding five of the leads 48 thereby to apply the potential of the source 24 across the electrostrictive slabs of the printing elements 18D, 18A, 18C, 18B, and 18E. As may be observed in FIG. 3, the selected printing elements 18 are those which form the numeral 3 (FIG. 5). The voltage signal from the source 24 establishes an electric field across these five slabs 10 of the printing elements 18D, 18A, 18C, 1813 and 18B which are distorted in a manner described hereinbefore. Those selected printing elements 18, being blocked at the upper end of the case 38 by the support member 16, expand Within the case 38 such as to cause a movement of the type elements 28 in a downward direction as illustrated by the dotted line 78. This growth or expansion of the selected printing elements 18 acts through the inked ribbon 64 to impress the numeral 3 on the paper 66. In similar manner, other characters may be formed by selectively actuating the printing elements 18. A suitable pulse voltage source may be used, if desired, to insure a quick return of the actuated printing elements 18 to their normal state.

It may be desirable to employ the actuator 58 to operate simultaneously with the expansion of the selected printing elements 18 to cause the striking bar 62 to drive in an upwardly direction in the drawing such as to drive the paper 66 and inked ribbon 64 against the selected type elements 20 that have been expanded so as to protrude downward below those that are not selected.

By thus selectively expanding the appropriate printing elements 18, numerical characters may be formed on a printing surface 66. The printing surface 66, such as paper, may be either stationery and have the appropriate electrostrictive elements forced against it through the inked ribbon M, or conversely, the striking bar 62 may be used to aid in the printing process by forcing the paper 66 against the letters formed by the expanded printing elements 18.

The particular physical configuration of the electrostrictive printing elements 18 within the casing 38, illustrated in FIGS. 2 and 3 for use in the printer of FIG. 4, is a relatively simple configuration employed to simplify the drawing. A somewhat more complex configuration of the printing elements 18 is illustrated in FIG. 6 which is a bottom end view of the type assembly 36 appearing in FIG. 3. Thus, in FIG. 6, the type assembly 36 includes 14 type elements 181 through 114, inclusive. The type elements 181 through 114, inclusive, are arranged in a configuration to form aplhanumeric characters including the letters A through Z, the numerals 0 through 9, and the plus and minus signs. These characters are illustrated in simple outline form by FIG. 7. Each of the type elements 181 through 110, inclusive, is driven by individual ferroelectric slabs (not shown) of the same type as illustrated in FIGS. 1, 2, and 3. The individual ferroelectric slabs (not shown) may be positioned in the same configuration as the type elements 101 through 114 and fixed in position by a potting and minus symbols.

compound. The first six type elements 101 through 106, inclusive, are arranged to form a rectangle wherein two of the type elements 101 and 104 form the horizontal sides in the drawing and the remaining four elements 182, 103, 105 and 106 are connected end to end in pairs to form the two sides of the rectangle. The rectangle has two diagonal members formed by the elements 112 and 108 connected end to end from the lower left corner to the upper right corner and the type elements 110 and 114 connected end to end from the upper left corner to the lower right corner. In similar manner, an additional two elements 109 and 113 are placed end to end vertically in the center of said rectangle and the final two type elements 107 and 111 are placed end to end horizontally in the center of said rectangle.

By selectively actuating the ferroelectric elements that are positioned to drive each of the type elements 101 to 114, inclusive, the several alphanumeric characters including the plus and minus symbols are imprinted by the printer illustrated in FIG. 4. It will be noted that since the type elements 181 to 114, inclusive, are being viewed from the botom end of the type assembly 36 (FIG. 4) that the type element actuated will form letters appearing to the reader as reversed. If, for example, it is desired to form the letter K, the type elements 185, 105, 187, 118 and 112 are actuated such that the letter K as appears in FIG. 7 is imprinted on the printing surface 66 (FIG. 4).

A matrix suitable for driving the several type elements 101 through 114, inclusive, illustrated in the type assembly 36 of FIG. 6 is shown in a schematic diagram in FIG. 8. The schematic diagram of this driving matrix replaces the keyboard 54, the decoding matrix 52, the lines 5'6, the switch 50, and the source of potential 24, that are illustrated in block form in FIG. 4. In FIG. 8 a source of potential 128 is connected through individual switches 122 which may be thought of as representing the respective alphabetical characters A through Z, inclusive, numerals 0 through 9, inclusive, and the plus Each of the switches 122 may be actuated by individual typewriter keys on a typewriter (not shown). Each of the switches connects the positive terminal of the source 120 (the other terminal being connected to ground), through several diodes to the upper plates 14 of one or more of the ferroelectric slabs 18 that are employed to actuate the respective type elements 191 through 114, inclusive. The lower plate 12 of each of the ferroelectric slabs 10 illustrated in FIG. 8 is connected to ground to complete the circuit.

Let us now consider the matrix structure of FIG. 8. The first switch 122 which is actuated by a typewriter key to print the plus symbol, connects the battery 128 to those vertical matrix lines 124 connected to the type elements 107, 189, 111, and 113. Similarly, the second switch 122 prints a minus symbol by applying the positive potential of the battery 128 through two diodes 128 to those vertical matrix lines connected to the type elements 187 and 1 11. The numeral 0 switch 122 when actuated by the zero type key (not shown) connects the positive potential of the battery 124) through six diodes 13h poled in the forward-conducting direction to pass the potential of the battery 120 to the first, second, third, fourth, fifth, and sixth vertical matrix lines 124. This act-uates the ferroelectric slabs Ill of the type elements 181 through 186, inclusive, and prints the numeral zero.

The numeral 1 switch 122, when actuated by the 1 key (not shown) connects the positive potential of the the source 128 through two diodes 132 poled in their forward-conducting direction to pass the potential of the source 128 to the ninth and thirteenth vertical matrix lines 124. These actuate the ferroelectric slabs 18 of the type elements 189 and 113, respectively, thereby causing the numeral tobe printed.

The numeral 2 switch 122 when actuated by its type key (not shown) connects the positive potential of the source 120 through five diodes 13 4 poled in their forward-conducting direction to apply the potential of the battery 120 to the first, fourth, fifth, seventh and tenth vertical matrix lines 124. These actuate the terroelectric slabs 10 of the type elements 101, 104, 105, 107 and 110 which form the numeral 2.

Similar connections are made by the remaining switches 122 when closed by their corresponding typewriter keys (not shown) to connect the source 120 to the necessary vertical matrix lines 124 to actuate the ferroelectric slabs 10 of the corresponding type elements .101 to 114, inclusive, and hence form the desired numeral or letter. Thus, the numeral 3 switch 122, acting through the matrix diodes 136, actuates the type elements 101, 104, 110 and 112 which print the numeral 3. Similarly, the numeral 4 switch 122 acting through five matrix diodes 138 act'uates the type elements .102, 103, 106, 107, and 11-1 which print the numeral 4. The numeral 5 switch 122, acting through the five matrix diodes 140, actuates the type elements 101, 103, 104, 108, and 111 which print the numeral 5. The numeral 6 switch 122, acting through the seven matrix diodes 14-2,. actuates the type elements 101, 103, 104, 105, 106, 107 and 111 which print the numeral 6. In like manner, the numeral 7 switch .122, acting through three matrix diodes 144, actuates the type elements 101, .110 and 114 which print the numeral 7. Further, the numeral 8 switch 122, acting through the eight matrix diodes 146, actuates the type elements 101 through 1117, inclusive, and 111 which print the numeral 8. Finally, the nu meral 9 switch 122 applies the potential of the source 120 through the seven matrix diodes 148 to actuate the type elements 101, 102, 103, 104, 106, 107 and 111 which print the numeral Considering now the formation of the alphabetical characters with the matxrix of FIG. 8, the letter A switch 122 applies the potential of the source 120 through the seven matrix diodes .150 which actuate the corresponding type elements 101, 102, 103, 105, 106, 107 and 111 and print the letter A. The letter B switch 122 applies the potential of the source 120 through seven matrix diodes 152 to actuate the type elements 101, 104 to 107, inclusive, 110 and 112 which print the letter B. Next, the letter C switch 122 applies the potential of the source 120 through the four matrix diodes 154 to actuate the type elements 101, 104, 105, and 100 necessary to form the letter C. Similarly, the letter D switch 122 applies the potential of the source 120- throu-gh five matrix diodes 156 necessary to actuate the type elements 101, 105, 106, 110 and 114, respectively, and print the iletter D. :In like manner, the letter E switch 122 passes the potential of the battery 120 through the five matrix diodes .158 to actuate the type elements 101, 104 to 107, inclusive, and print the letter E.

The letter F switch 122 applies the potential of the source 120 through the four matrix diodes 160 to actuate the type elements 101, 105, 106 and 107 and print the letter F. The :letter G switch 122 applies the potential of the source 120 through the six matrix diodes 162 that are necessary to actuate the type elements 101, 103 to 106, inclusive, and 111 which form the letter G. 'In like manner, the iletter H switch 122 applies the potential of the source 120 through the six matrix diodes 164 to actuate the type elements 102, 103, 105, 106, 107, and 111 and thus print the letter H. The leter I switch 122 applies the potential of the source 120 through the two matrix diodes 168 which in turn actuate the type elements 109 and 113 and print an I. In like manner, the letter 1 switch 1 22 applies the potential of the source 120 through the tour matrix diodes 170 which energize the type elements 102 through 105, inclusive, thereby to print the letter J.

The letter K switch 122 applies the potential of the source 120 through five matrix diodes 172 to actuate the slabs 10 of the type elements 105, 106, 107, 110 and 112 and print the letter K. The letter L switch 122 applies the potential of the battery 120 through the three matrix diodes 174 that are necessary to actuate the slabs 10 of the type elements 104, and 106 and print the letter L. In like manner, the letter M switch 122 applies the potential of the battery 120 through the six matrix diodes 176 that actuate the slabs 10 of the type elements 101, 103, 105, 100, 103, and and hence form the letter M. The letter N switch 122 is connected to apply the potential of the source through the six matrix diodes 178 to actuate the slabs 10 of the type elements 102, 103, 105, 105, 108 and 112 and hence print the letter N. The letter 0 switch 122 is connected to apply the potential of the source 120 through the six matrix diodes 180 to actuate the slabs of the six type elements 101 to 106, inclusive, thereby to form the letter O.

The letter P switch 122, when actuated, applies the potential of the source 120 through the six matrix diodes 182 that are connected to actuate the slabs 10 of the six type elements 101, 102, 105, 106, 107 and 111 that are necessary to form the letter P. The letter Q is somewhat more complex and its switch 122 applies the potential of the source 120 through the seven matrix diodes 184 which are connected to the plates 14 of the slabs 10 of the type elements 101 through 106, inclusive, and 112 to form the letter Q. in like manner, the letter R switch 122 applies the potential of the source 120 through the seven matrix diodes 186 to energize the slabs 10 or" the corresponding type elements 101, 102, 105, 106, 107, 111 and 112 to form the letter R." The letter S switch 122 applies the potential of the source 120 through six matrix diodes 188 to actuate the corresponding type elements 101, 103, 104, 105, 107 and 111 which print the letter S. The letter T switch 122 applies the potential of the source 120 through the three maxtrix diodes 190 which are connected to the slabs 10 of the type elements 101, 109 and 113 and hence form a T.

The letter U switch 122 applies the potential of the source 120 to the five matrix diodes 192 which in turn are connected to establish electric fields across the slabs 10 associated with the type elements 102 through 106, inclusive, and hence print the letter U. In like manner, the letter V switch 122 applies the potential of the source 120 through the four matrix diodes 194 to actuate the type elements 105, 106, 110 and 114 and print the letter V.

The letter W switch 122 applies the potential of the battery 120 through the six matrix diodes 196 to the slabs 10 which drive the type elements 102, 103, 105, 106, 112 and 114 to form the letter W. The letter X switch 122 applies the potential of the source 120 through the four matrix diodes 108 which are connected to the slabs 10 of the type elements 105, 110, 112 and 114 to form an X. The letter Y is formed by its switch 122 applying the potential of the battery 120 through the three matrix diodes 200 which are connected to energize the slabs 10 of the type elements 108, 110 and 113 and hence to form the letter Y. Finally, the letter Z switch 122 applies the potential of the source 120 through the four matrix diodes 202 which in turn are connected to the slabs 10 of the type elements 101, 104, 110 and 114 which form the letter Z.

It may thus be seen that by selectively closing the switches 122 for the various characters, the matrix of FIG. 8 selectively applies the potential of the source 120 across only those slabs 10 corresponding to the character selected by the switch 122.

Other configurations of the type elements 101 to 114, inclusive, will be apparent to those skilled in the art by which the same or similar characters can be formed by selectively exciting different electrostrictive slabs 10 to drive associated type elements and thereby to form or print characters. Alternatively, of course, a given type element may have an entire character raised on its face which is printed when that type element is energized by its associated electrostrictive slab.

To achieve line-by-line printing, a plurality of the type units 36 (FIG. 4) may be placed in side-by-side relationship along the line of printing; each assembly may be driven by circuitry of the type illustrated in FIG. 4. The technique of this invention may be applied to typewriters, if desired, wherein the striking bar 62 illustrated in FIG. 4 may be the carriage of a typewriter which moves the paper with respect to the type member 36 in the conventional manner. In this instance, the numerous type members employed in present day typewriters could be replaced by the single type assembly 36 which is selectively actuated by electronic switching means.

There has thus been described a relatively simple solid state printer having a relatively small number of mechanical parts and thereby having a greatly improved reliability.

Since many changes could be made in the above construction and many apparently widely difierent embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. An apparatus for printing characters comprising:

a type unit including a type element,

a transducer unit mounted to directly actuate said type unit,

said transducer unit including an elongated member comprising an electrostrictive material,

said elongated member having a fixed end in said transducer and a free end,

said free end being disposed adjacent to and in movable relation with said type element,

said elongated member having electrodes thereon susceptible of sustaining relatively high differences of potential therebetween, and

said free end of said elongated member being movable in response to an actuating signal applied to said electrodes thereby directly disposing said type element for a printing operation.

2. The apparatus of claim 1 and further comprising:

electric energizing means coupled to said transducer for applying said actuating signal to said electrodes.

3. The apparatus of claim 2 and further comprising a work member,

said type unit and said work member being susceptible of relative displacements,

and an inked ribbon positioned adjacent to said type unit.

4. The apparatus of claim 3 wherein said electrostrictive material is a ferroelectric ceramic.

5. An apparatus for printing characters on the surface of a work member comprising:

a type unit including a type element disposed adjacent to said surface,

said type element and said work member being susceptible of relative displacements,

a transducer unit mounted to directly actuated said type unit,

said transducer unit including an elongated member comprising an electrostrictive material,

said elongated member having a fixed end in said transducer and a free end,

said free end being disposed adjacent to said type element,

said elongated member having electrodes thereon susceptible of sustaining relatively high differences of potential therebetween, and

said free end of said elongated member being movable in response to a change in the difierence of potential between said electrodes thereby directly disposing said type element for a printing operation.

6. An apparatus for printing characters comprising:

a type unit including a plurality of type elements disposed in a predetermined arrangement,

a transducer unit mounted to directly actuate said type unit,

said transducer unit including a corresponding plurality of elongated members,

each elongated member comprising an electrostrictive material and having a fixed end in said transducer and a free end,

each of said free ends being disposed adjacent to and in movable relation with a corresponding type element,

each of said elongated members having electrodes thereon susceptible of sustaining relatively high diiierences of potential therebetween, and

each of said free ends of said elongated members being movable in response to a change in the difierence of potential between said electrodes thereby directly disposing its corresponding type element for a printing operation.

7. The apparatus of claim 6 and further including electric means coupled to said transducer for selectively applying actuating electric signals to said electrodes thereby selectively disposing difierent groups of said type elements for consecutive printing operations.

8. The apparatus of claim 7 and further including a work member,

said type unit and said work member being susceptible of relative displacements, and an inked ribbon positioned adjacent to said type unit.

9. An apparatus for printing characters on the surface of a work member comprising:

a type unit including a plurality of type elements disposed in a predetermined arrangement adjacent to said surface, I

said type elements and said work member being sus ceptible of relative displacements,

a transducer unit mounted to directly actuate said type unit,

said transducer unit including a corresponding plurality of elongated members,

each elongated member comprising an electrostrictive material and having electrodes thereon susceptible of sustaining relatively high differences of potential therebetween,

each of said elongated members having a fixed end in said transducer and a free end,

each free end being disposed adjacent to and in movable relation With a corresponding type element, and

each of said elongated members being movable in response to a change in the difference of potential between its electrodes thereby directly disposing its corresponding type element for a printing operation.

10. The apparatus of claim 9 and further including electric means coupled to said transducer for selectively applying actuating electric signals to said electrodes thereby selectively disposing diiterent groups of said type elements for consecutive printing'operations.

11. The apparatus of claim 10 and further including means mechanically coupled to said work member for displacing said surface toward said type unit thereby to aid in said printing operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,001,124 Cooke May 14, 1935 2,578,286 Chrisholm Dec. 11, 1951 2,792,779 Toeppen et a1 May 21, 1957 2,835,761 Crownover May 20, 1958 2,942,928 Levin June 28, 1960 

1. AN APPARATUS FOR PRINTING CHARACTERS COMPRISING: A TYPE UNIT INCLUDING A TYPE ELEMENT, A TRANSDUCER UNIT MOUNTED TO DIRECTLY ACTUATE SAID TYPE UNIT, SAID TRANSDUCER UNIT INCLUDING AN ELONGATED MEMBER COMPRISING AN ELECTROSTRICTIVE MATERIAL, SAID ELONGATED MEMBER HAVING A FIXED END IN SAID TRANSDUCER AND A FREE END, SAID FREE END BEING DISPOSED ADJACENT TO AND IN MOVABLE RELATION WITH SAID TYPE ELEMENT, SAID ELONGATED MEMBER HAVING ELECTRODES THEREON SUSCEPTIBLE OF SUSTAINING RELATIVELY HIGH DIFFERENCES OF POTENTIAL THEREBETWEEN, AND SAID FREE END OF SAID ELONGATED MEMBER BEING MOVABLE IN RESPONSE TO AN ACTUATING SIGNAL APPLIED TO SAID ELECTRODES THEREBY DIRECTLY DISPOSING SAID TYPE ELEMENT FOR A PRINTING OPERATION. 